1. Field of the Invention
The present invention relates to a zoom lens and an image pickup apparatus equipped with the same.
2. Description of the Related Art
Zoom lenses having variable angles of view and image pickup apparatuses equipped with such zoom lenses are known. In some zoom lenses, internal focusing is adopted. In internal focusing lenses, the lens unit located closest to the object side is stationary during focusing, and a lens unit(s) other than this lens unit is (are) moved for focusing.
Whatever the focusing scheme may be, moving a lens unit (s) generates noise such as sound of movement of the lens unit(s). In addition, a driving mechanism for moving the lens unit(s) also generates driving noise.
The noise generated with movement of the lens unit(s) can be made relatively small in the internal focusing lens. Therefore, the level of noise in the sound recorded with shooting (of moving images) can be made low. For this reason, internal focusing is adopted in many optical systems for video cameras. An example of the zoom lens using internal focusing is disclosed in Japanese Patent Application Laid-Open No. 2011-197058.
While typical video cameras of several years ago only have the function of video shooting, recent models typically have the function of still image shooting in addition to video shooting. Likewise, while typical digital still cameras of several years ago only have the function of still image shooting, recent models typically are capable of selectively shooting still images and videos.